Realistic applications.
WHAT THE GENUINE CANDIDATES ARE
Simulating quantum systems: molecules, materials, chemistry
Certain optimisation problems Some machine learning tasks, provisionally Breaking specific cryptographic schemes
WHY SIMULATION IS THE STRONGEST CASE
Quantum systems are naturally expensive to simulate classically, and a quantum machine simulates them directly.
WHAT THAT COULD AFFECT
Drug discovery Catalyst and battery design Materials science
WHAT THE OPTIMISATION CASE IS
Less certain. Many claimed advantages have been matched by improved classical methods.
WHAT TO BE CAUTIOUS ABOUT
Claims that quantum computing will transform business analytics, logistics or finance imminently.
WHY
The problems are real, but the advantage is unproven at useful scale.
WHAT THE CRYPTOGRAPHIC CASE IS
The one with a definite, understood algorithm and a definite consequence.
WHAT THAT CONSEQUENCE IS
The public-key cryptography protecting the internet today becomes breakable, given a sufficiently large machine.
WHEN THAT MIGHT HAPPEN
Unknown, and estimates vary by decades.
WHAT TO DO ABOUT IT ANYWAY
Plan the transition, because data captured today may be decrypted later.
